


Colonel Mustang’s Forbidden Omega

by Mermaid886



Category: Fullmetal Alchemist (Anime 2003), Fullmetal Alchemist - All Media Types, Fullmetal Alchemist: Brotherhood & Manga
Genre: Alpha Roy Mustang, Alpha/Beta/Omega Dynamics, Alpha/Omega, Angst, Dominant Roy Mustang, F/M, Fluff and Smut, Hurt/Comfort, Omega Riza Hawkeye, Riza loves him back, Roy loves Riza, Royai - Freeform, Unplanned Pregnancy, royxriza - Freeform
Language: English
Status: Completed
Published: 2020-02-02
Updated: 2020-03-07
Packaged: 2021-02-28 05:55:47
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 3
Words: 3,260
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22518856
Author URL: https://archiveofourown.org/users/Mermaid886/pseuds/Mermaid886
Summary: Everyone knew that Roy Mustang and Riza Hawkeye wanted to be more than friends, but their allegiance to their country always kept them apart. When Roy, a strong alpha, discovers that Riza is an omega and finds her in the middle of her heat, will the two be able to resist each other or will they jeopardize their military careers for love?
Relationships: Riza Hawkeye & Roy Mustang, Riza Hawkeye/Roy Mustang
Comments: 2
Kudos: 56





	1. Chapter 1

Thanks for reading! I don’t own any of Fullmetal Alchemist! Please let me know if you enjoy! Updates every other Saturday!  
—————————————————————

Colonel Roy Mustang sighed to himself as he walked down the hallway towards his office in the military building of Central.

It had been a long day.

Actually, it had been a long week, a long month.

Roy Mustang had been assigned a difficult mission and recently, he had been traveling a lot.

Traveling was difficult when Riza Hawkeye, his lieutenant and first choice of a partner, couldn’t go with him.

Riza helped Roy more than most people realized, she was like his right hand.

But instead of traveling with Colonel Mustang, Riza had been stationed at Central, forcing the two to communicate over the radio.

That was fine, of course.

It wasn’t like Roy needed to talk to Riza in person…...

…...It was just better if he could.

Roy set his jaw as he walked down the hallway, visions of Riza bearing her back to him all those years ago flashed through his mind.

Roy often thought of that moment.

In fact, Roy thought of Riza far more often than he should.

They could never be together.

It was silly for Roy to dream differently, but it was natural.

Roy was an alpha, just like most members of the military.

Strong, dominant, dedicated, possessive, proud, and courageous, those were traits that made a good soldier.

Naturally, alphas did very well with the job.

Roy stopped in the hallway when he heard a noise.

A strange, scraping noise.

It was late, and most personnel should have left by now…….

Roy scowled.

Standing in the silent hall, Colonel Mustang listened closely, waiting to see if the noise would occur again.

“Hello?” Roy called out in his deep voice. “Who’s there?”

Roy heard the clink of something metal and then hasty footsteps, running down the hall just around the corner towards the Fuhrer’s office.

It was at night that the Fuhrer’s door was left unlocked for the cleaning staff to access…….

Roy growled and clenched his fist, darting off to pursue the footsteps.

Who was in there?!

A spy?!

A disgruntled soldier wanting to sell Amestris’s secrets?!?

Who was…….

Roy stomped towards the Fuhrer’s office, his brow firmly knitted together as he watched the door swing behind whoever just entered.

If Roy was anything, he was loyal to his country.

Roy grit his teeth as he turned the doorknob.

Who was stupid enough to think that they-

The second that Roy opened the door, he stopped.

A delightful chill crawled up Roy’s spine and he found himself trying hard to remember how to breathe.

The scent of an omega………

A wanting, waiting, desperate omega…...

Roy’s alpha brain tried to think through the haze of hormones that flooded his system, the fog of the pheromones he was inhaling made it very difficult.

An omega……

…….In the military?!?

That’s why…..that’s why this person had been running.

They weren’t trying to steal, they were trying to escape.

“Come out.” Roy coaxed.

Roy’s voice was more like a growl than a statement.

He paused to clear his throat, but his voice still rumbled deep from his chest. “Come out, I’m not going to hurt you.”

The room remained silent.

Roy shifted on his feet trying to adjust his trousers which suddenly felt uncomfortably tight.

Forcing himself to stay sane, Roy called out again, “Come out, I can escort you to safety. Please, you have my word as a member of the Amestris military.”

Another long moment of silence passed and Roy swallowed the extra saliva in his mouth, causing his throat to go dry.

Colonel Mustang was just about to call out again when a small voice answered, “Roy?”

Roy’s eyes widened.

No……….

It couldn’t be…….

The voice came from behind the Fuhrer’s desk.

Roy Mustang’s body felt like lead as he trudged over and peered down.

There, huddled under the heavy furniture, with flushed cheeks and tempting pink lips, sat Riza Hawkeye, staring back up at him. “Roy....”

“Riza?” Roy asked in a breathless gasp.

This was not good.

The attraction between Roy and Riza already borderlined on undeniable. 

There had been many times over the years when both of them had problems holding back.

Was Riza really an omega?!?!

Oh dear.

Oh no….

“Roy, I need you.” Riza pleaded with sad, tearful eyes.

…..Beautiful, large, brown eyes that Roy had always admired.

Roy sunk to his knees while Riza melted him with her stare, begging him to relieve her of her pain, just like she had when she asked him to take that map off of her back years ago……

Roy had been fascinated with Riza ever since, and she with him, but the two had never said that out loud.

Would they ever?

“Riza…….” Roy breathed thickly.

Roy's hands trembled with the desire to reach out and touch Riza’s face, to pull her into his arms…..

To have her as his own…..

If they were caught, they would both be ejected from the military in shame.

Then what?

Then what?!?

“Roy, please!” Riza all but begged, leaning forward and letting Roy get a whiff of her lily perfume.

Roy knew the scent well but at the moment, it just made him crazier……

Roy couldn’t think…..

Roy couldn’t reason….

All Roy could do was feel and want….

Colonel Mustang needed to make a decision and this time, Riza was only making things worse~.


	2. Chapter 2 - Under the desk

Thanks for reading! I don’t own any of Fullmetal Alchemist! Please let me know if you enjoy! Updates every other Saturday!  
————————————————————

Roy was still having trouble speaking as Riza lured him in with her brown eyes and delicious perfume.

“Ri…...Riza…..” Roy gasped hoarsely.

Roy hadn’t felt this helpless in a long time.

Helplessness was not a sensation that Roy Mustang was accustomed to nor was it one that he was comfortable experiencing.

Roy was normally stoic and steadfast, a committed officer who served the military with an unmatched loyalty.

But……

Roy was human…..

And the woman that he had always loved, yes, Roy had secretly admitted to himself a long time ago that he loved Riza Hawkeye, was an omega and……

She was right in front of him.

Begging.

“Roy….” Riza called out again, her voice softer than Roy had ever heard it before.

The sound made Roy’s racing heart pound even faster.

“Ri…Riza….we….we can’t…..Not here….” Roy tried to reason, swallowing thickly.

Riza didn’t like that Roy was denying her.

With a disappointed mewl, Riza boldly grabbed ahold of Roy’s collar and pulled him in close, kissing him forcefully.

Riza’s lips may as well have been poison.

After that first sting, Roy was gone.

It didn’t matter that it was the Fuhrer’s Office.

It didn’t matter that it was the Fuhrer’s desk. 

All Roy And Riza cared about in that moment was that they had to be together.

Denying themselves for so long, the magnetic attraction between alpha and omega finally won out.

It was hard to tell who was pushing who, who was encouraging who, who was the aggressor.

Riza bit her lip, her eyes squeezed tightly shut while Roy claimed her as his omega there under the Fuhrer’s desk.

If it had to happen, it would have been much better if they could have gone back to Riza’s apartment or Roy’s place, but……..

Neither alpha nor omega could wait that long.

Roy could feel himself sweating through his uniform as he kissed Riza deeply, holding her close while they made love.

Riza was stripped down to her black shirt and panties, but Roy tried to keep his clothing mostly intact, just in case he heard footsteps in the hallway……..

Roy clamped his hand over Riza’s mouth while they rode out their bliss together, gritting his teeth when she bit his hand gently.

Riza and Roy were both breathing hard when he slowly pulled himself from her body.

For a long moment, they locked eyes.

It was done.

Roy and Riza had committed the act that the military would see as unforgivable……..

They had admitted their love for each other, physically acknowledged it in the deepest way.

Not a word passed between them as Roy helped Riza dress.

…..Partially because they didn’t want anyone who happened to be passing by in the hallway to hear and partially because the force of their coupling stripped their voices.

Roy had Riza back in her uniform in seconds, and to Riza’s surprise, he opened a window in the Fuhrer’s office and guided them down to the street, using the rooftops of Central instead of the hallways.

Riza followed him confidently, after all, Roy had closed the window behind them, they had been careful to leave no trace behind.

No one would ever know what had happened underneath the Fuhrer’s desk…..

By the time they reached the ground, Riza whimpered and doubled over.

A look of concern flashed across Roy’s face and he gathered his new mate into his arms while thunder rolled in the sky.

An omega’s heat wasn’t resolved in minutes……..

Roy had to move quickly.

Dashing through the streets with Riza in his arms, Roy quickly made his way to her apartment.

Riza already started to claw at Roy’s uniform while he unlocked her door, using the key from her pocket.

Riza’s dog looked on wide-eyed as the couple slammed the door shut behind them and stumbled into Riza’s bedroom kissing passionately and shedding clothing.

While the rain began to beat against the window, Riza heard her own heart beating in her ears while Roy took her over and over, claiming her as his own.

It felt amazing, but it was far more satisfying than just pure physical pleasure.

Riza thought it felt so good to taste Roy’s kiss and to feel his hands on her…...because that was where they had always belonged.

—————————————————————

Late in the night, after Riza’s hormones momentarily calmed down, the couple laid in her disheveled bed, exhausted and drained from their exertion.

Roy was on his back and Riza was cuddled onto his chest, listening to his pulse beat strong and steady in her ears. 

Roy’s fingers gently trailed along Riza’s tattooed back while they snuggled together, listening to the rain.

“Bet you never thought you’d see this again.” Riza said quietly, referring to the tattoo on her back.

“I always hoped that I would.” Roy confessed softly.

“What are we going to do, Colonel?” Riza sighed, gently passing her hand over Roy’s chest, letting her fingers slide across the hard muscles of his abdomen.

“Right now we’re going to sleep, Lieutenant. “ Roy said very matter-of-factly, closing his eyes.

Riza frowned and looked up at Roy.

Roy seemed to be peacefully on his way to sleep as if he didn’t have a care in the world.

“Roy, I’m serious!” Riza snapped.

Roy’s eyes cracked open and he looked at Riza intently.

It was like an unstoppable force meeting an immovable object……..

What to do?

Roy and Riza could never be together publically, both of them would be discharged, maybe even put on trial for crimes against the military for participating in such disorderly conduct.

However, as Roy And Riza looked at each other, they both knew the truth.

Now that they were finally together, neither was going to give the other up.

Roy and Riza were alpha and omega now.

They would marry in a heartbeat if only their union would be allowed.

If only…

Roy would never ask Riza to abandon her career and of course, Riza would never ask Roy to either, especially since they were considering him for the position of Fuhrer once Grumman left office in a few years……

“I don’t know what we’re going to do, Riz” Roy said with a frown.

Riza’s face started to fall before Roy added, “All I know is that we’re going to stay together, somehow.”

Riza gave Roy a soft smile. “We’ve been together for a long time, Roy.” 

Riza was right, they had been together for many years now.

Not just in their service to the military.

Roy and Riza had held one another in their hearts since they first met, both of them refusing to seriously date.

People thought that they were just kindred spirits, or loners, or workaholics…………

While both Roy and Riza could be all of those things at times, they were really just waiting on each other.

Roy gave Riza a gentle kiss and added, “But we really do have to sleep. You know we have drill in the morning. But I guess you could take a leave day and have it excused.”

“No, that’ll make it look more suspicious if anyone finds anything.” Riza said quickly.

“What do you think they’re going to find, Riz?” Roy asked, furrowing his brow.

“I don’t know...hopefully nothing.” Riza yawned, laying down on Roy’s chest.

Roy tangled his fingers in Riza’s soft blonde hair and kissed her head gently.

“I love you, Riza.” Roy whispered huskily before they fell asleep.

“I love you too, Roy.” Riza replied quietly. 

Roy and Riza both smiled softly while they slept that night.

And the next morning when they woke, in spite of the danger that they were now facing, both Roy and Riza felt more rested than they had in years.


	3. Chapter 3 - Happy

Thanks for reading! I don’t own any of Fullmetal Alchemist! Please let me know if you enjoy!  
—————————————————————

Fuhrer Grumman narrowed his eyes and peered incredulously at Roy while he spoke. “Are you positive you didn’t see anything, Colonel? You were on watch last night.” 

“Positive, sir. I didn't see anything suspicious.” Roy said honestly, staring straight ahead as he stood at attention.

Roy was currently in Fuhrer Grumman’s office, standing a few feet away from the very desk that he and Riza had become one under the night before.

Roy had thought they had been careful…..

He and Riza had escaped through the window, he had closed the window, and they were able to make their way down to the street……

…..But Roy had overestimated himself.

In the heat of passion, Roy had closed the window but he had forgotten to latch it.

In the middle of the night, the window had blown open, sending leaves and rain all over Fuhrer Grumman’s office and desk, making it apparent that someone had been in the room on unauthorized business.

Questioning had started as soon as everyone had reported for duty the following morning.

Riza had already undergone her interrogation and no one seemed to suspect anything, but Roy was grilled more thoroughly.

It had been Roy’s shift on watch after all.

“I see.” Grumman said after a long, tense silence. He gave Roy a calculating stare before he added, “Very well, Colonel. If you find any information, please, let me know immediately.”

“Of course, sir.” Roy said stoically.

“Dismissed.” Grumman said in a suspicious tone.

Roy saluted and then turned on his heel and left.

That was close…….

Nothing had gone missing from the Fuhrer’s office.

Nothing was destroyed, except for some minor water damage to the desk and the carpet.

No one would come forward about last night because there was no one except for Roy and Riza involved.

Roy passed Riza in the hallway later in the afternoon and both of them exchanged a brief, longing glance. 

Maybe this would all blow over……..

If everyone just moved on, then so could Roy and Riza.

Hopefully……,,

————————————————————

Roy was right.

No one came forward about the open window, no one offered any information, no one found any clues.

Eventually, Fuhrer Grumman blamed himself and said that maybe he forgot to close the window before he left for the day.

Roy and Riza were secretly cheering.

They hadn’t been discovered!

Not yet……

They met in secret at Riza’s apartment each night, taking different routes there in case they were watched when they left the military building.

Most nights, Roy arrived at Riza’s apartment with something in his arms.

Something, anything that served as a decoy to his true purpose there.

A paper, a bag containing nothing but stuffed full of tissue paper to look like a parcel, some common household supplies……

Each night, Roy carried an excuse with him to Riza’s apartment.

That way, in case Roy was caught coming or going, he could always have the excuse that he was just returning something to his coworker, or that he was borrowing some household supplies.

Roy would ring Riza’s doorbell, she would greet him, they would exchange a short, polite conversation, then Roy would invent an excuse to step into Riza’s apartment.

Once Riza closed the door and they were safely out of the angle of any potential camera, that was when it was all worth it….

Roy and Riza would embrace each other and share a deep kiss, then they’d cook dinner together and talk about their day, ending the evening later by cuddling and showering together, just like any other couple.

Domestic bliss.

Was that really a crime?

Roy and Riza realized that if anyone was watching them closely, then the colonel and lieutenant would both be caught.

…...But that was a chance that Roy and Riza were willing to take.

————————————————————

Things were tumultuous at best for a while.

Riza and Roy continued their affair, barred from marriage and true happiness by their dedication to their country and to their work.

But they couldn’t hide forever.

As careful as they tried to be, Riza became pregnant.

On the day that they found out about Riza’s condition, the couple spent that night in anguish, talking and deciding carefully. 

The couple both went to work the following day with the intention of resigning.

Riza would be dismissed as soon as everyone discovered her new secret and Roy didn’t think it would be fair if he was allowed to stay somehow and she had to go.

With solemn faces, Roy and Riza walked together up the stairs towards the Fuhrer’s office when they were met by a very overexcited Major Armstrong in the hallway.

“Mustang! Why so glum?!? Have you not heard the news?!” Major Armstrong thundered.

Neither Roy nor Riza were in the mood for his exuberance. 

“News?” Roy asked blankly.

Their careers were about to end, they had a baby on the way with no income now, what did Roy or Riza care about the news?

“Grumman resigned at midnight! You’re in, Mustang! They chose you! Congratulations!” Major Armstrong roared, giving Roy a hard slap on the shoulder.

“What are you talking about?!” Roy shouted in irritation while Riza blinked.

“I said they chose you!” Major Armstrong laughed with joy. “You’re going to be Amestris’s new Fuhrer, Mustang!”

Riza’s eyes widened.

Was……..

Was that really true?!?

Could it be?!?

Roy’s jaw fell open.

How much shock could one man take in twenty-four hours?!?

—————————————————————

Major Armstrong’s report was correct.

Roy became the new Fuhrer of Amestris, allowing Riza to step down honorably from her post as Lieutenant to serve as the Fuhrer’s wife.

It wasn’t until after their marriage two weeks later that they announced Riza’s pregnancy…….

Roy was a good Fuhrer, a strong and wise leader, whom nearly everyone loved and respected.

Riza, although she was soon busy with their new baby, a sweet little boy with a full head of black hair, still acted as Roy’s right hand.

Finally, Roy and Riza could do what they dreamed while they served their country which they loved so much……..

As a couple…….

As a family……

They could be together.


End file.
